ncurses 5.9 - patch 20110716

ncurses 5.9 - patch 20110716

+ replace an assert() in _nc_Free_Argument() with a regular null
  pointer check (report/analysis by Franjo Ivancic).
+ modify configure --enable-pc-files option to take into account the
  PKG_CONFIG_PATH variable (report by Frederic L W Meunier).
+ add/use xterm+tmux chunk from xterm #271 -TD
+ resync xterm-new entry from xterm #271 -TD
+ add E3 extended capability to linux-basic (Miroslav Lichvar)
+ add linux2.2, linux2.6, linux3.0 entries to give context for E3 -TD
+ add SI/SO change to linux2.6 entry (Debian #515609) -TD
+ fix inconsistent tabset path in pcmw (Todd C. Miller).
+ remove a backslash which continued comment, obscuring altos3
  definition with OpenBSD toolset (Nicholas Marriott).